Distant pollution sources affect cloud formations
A team of researchers, including Livermore computer scientist
David Stevens, has determined a close tie between distant sources
of pollution and the formation of clouds that influence global
climate. The study focused on anvil cirrus clouds, an important
but poorly understood element of Earth’s climate system.
In this study, researchers used data from a National Aeronautics
and Space Administration (NASA) field experiment called CRYSTAL-FACE
(Cirrus Regional Study of Tropical Anvils and Cirrus Layers—Florida
Area Cirrus Experiment). The experiment obtained the first comprehensive
measurements of aerosols and cloud particles throughout the atmospheric
column during the evolution of multiple deep convective storm systems.
Detailed cloud simulations that resolve the size distributions
of aerosols and cloud particles were then made using the Livermore-developed
DHARMA code. The researchers found that most anvil ice crystals
form on midtropospheric aerosols—that is, on aerosols 6 to
10 kilometers above Earth’s surface. Scientists previously
assumed that the aerosols needed for cloud formation are suspended
closer to Earth’s surface.
This project was led by researchers from NASA’s Ames Research
Center and included collaborators from the National Center for
Atmospheric Research, University of North Dakota, Hampton University,
Universidad Nacional Autónoma de Mexico, Stratton Park Engineering
Company Inc., University of Denver, California Institute of Technology,
and Center for Interdisciplinary Remotely-Piloted Aircraft Studies.
The team’s findings were published in the April
30, 2004, issue of Science.
Contact: David Stevens (925) 422-7649 (firstname.lastname@example.org).
Gene-rich human chromosome-19 sequence completed
In the April
1, 2004, issue of Nature, a team of investigators,
including researchers from Lawrence Livermore and Los Alamos national
laboratories, described the completed sequencing of human chromosome
19, the most gene-rich of all the human chromosomes. The project
is part of a long-term collaboration led by the Department of Energy’s
(DOE’s) Joint Genome Institute (JGI) and the Human Genome
Center at Stanford University and included researchers from the
University of California at Santa Cruz; Children’s Hospital
and Research Center in Oakland, California; the Howard Hughes Medical
Institute at the University of Washington, Seattle; Case Western
Reserve University; and the National Cancer Institute.
Although chromosome 19 represents only about 2 percent of the human
genome, it has 55.8 million bases, or letters, of genetic code
and features nearly 1,500 genes. Embedded in the completed sequence
data are critical regulatory networks of genes tasked with controlling
such functions as repairing DNA damage caused by exposure to radiation
and to other environmental pollutants.
DOE originally selected chromosome 19 as a sequencing target to
investigate the link between DNA damage from radiation exposure
and human cancer. Livermore’s initial work, conducted in
the mid-1990s, led to mapping many of chromosome 19’s DNA-repair
genes. In 1999, DOE transferred the sequencing effort to JGI and
the finishing effort to Stanford. Finishing is the painstaking
process of ensuring that the information is completely contiguous
and all ambiguities are resolved.
The estimated error rate of the completed chromosome-19 sequence
is less than 1 in 100,000 base pairs, which far exceeds the 1 in
10,000 base-pair error rate established by the International Human
Genome Sequencing Consortium. This version of the sequence is thus
500 times better than previous drafts in terms of contiguity and
Contact: Susan Lucas (925) 296-5638 (email@example.com).
Counterintelligence effort receives excellent rating
Livermore’s Security Awareness for Employees (SAFE) Program
earned an excellent rating from the Department of Energy’s
(DOE’s) Office of Counterintelligence (OCI). It is the first
overall excellent rating ever garnered by a DOE National Nuclear
Security Administration counterintelligence office in such a thorough
The SAFE Program underwent an intensive audit by inspectors between
March 22 and April 1, 2004. OCI inspectors rated SAFE in 12 areas,
including management, operations, and liaison with other Laboratory
organizations. The inspection report noted SAFE’s significant
counterterrorism efforts during the past three years. According
to the report, the program’s liaisons with other Laboratory
organizations are particularly noteworthy, and its work with the
Federal Bureau of Investigation is outstanding.
Contact: Terry Turchie (925) 422-6366 (firstname.lastname@example.org).
Thunder achieves record cluster efficiency
Lawrence Livermore’s newest supercomputer, called Thunder,
debuted as the world’s second fastest supercomputer according
to the Top500 list released in June 2004. In benchmark testing,
Thunder achieved a sustained performance of 19.94 trillion operations
per second (teraops). Its theoretical peak speed is rated at 23
Thunder is a Linux cluster that runs an open source software environment
called CHAOS (Clustered High Availability Operating System), which
was developed by the Laboratory. The cluster has 1,024 nodes,
each with four Itanium 2 processors that offer processing speeds
up to 1.4 gigahertz. In tests, Thunder achieved a record cluster
efficiency of 86.9 percent, an important measurement in cluster
scalability. The complete Top500 list is available at www.top500.org.
Contact: Mark Seager (925) 423-3141 (email@example.com).